Nowadays, portable multimedia players such as MP3 players (MPEG-1 Audio Layer 3) become popular electronic devices in modern societies due to some advantages such as small size, light weightiness and easy portability. On account of their portability, the users can use such portable multimedia players everywhere they are. In order to hear songs from the portable multimedia player, some accessories such as earphones are indispensable. As known, the use of an earphone at a sufficiently high volume level may cause temporary or permanent hearing impairment. The extended period of using the earphone at improper intensity or frequency of the sound wave may be also damaging to the autonomic nerves of the user and thus reduce the sound discrimination capability or result in hearing loss. For preventing from the hearing damage during extended listening, some hearing experts advise the users to take a rest for at least 5˜10 minutes after 30-minute period of using earphones to listen to songs.
For reminding the user of the total time period of playing songs, some manufacturers of portable multimedia players have attempted to display the total time period on the screens of the portable multimedia players or the toolbars of the player software. According to these designs, the users need to personally view the total time period in order to realize whether the total time period exceeds 30 minutes. In most situations when the users listen to songs by using earphones, the users frequently forget to keep an eye on the total time period and thus the users seldom take a rest after 30-minute period of using earphones to listen to songs. On the other hand, if the users listen to songs without using earphones, the total time period shown on the screens of the portable multimedia players or the toolbars of the player software is usually meaningless because the possibility of resulting in hearing loss is largely reduced.